Mental health advocates and doctors who treat bipolar disorders say managing the condition can be complicated -- and they applaud Oscar-winning actress Catherine Zeta-Jones for seeking more help for her bipolar II disorder.

All kinds of things can trigger problems, from stress to irregular schedules, say doctors.

"It's great that she is getting help for herself and serving as a role model," says Ken Duckworth, medical director of the National Alliance on Mental Illness, a mental health organization based in Arlington, Va. "Every time light is shed on this illness, I think people's anxiety or sense of shame is reduced."

Zeta-Jones' spokeswoman, Cece Yorke, confirmed in an e-mail to USA TODAY this morning that "Catherine has proactively checked into a health care facility. Previously Catherine has said that she is committed to periodic care in order to manage her health in an optimum manner."

Bipolar disorder is a brain disorder that causes shifts in mood and energy, according to the National Institute of Mental Health. The mental illness, which was known as manic depression, can develop in the late teen years or early adulthood.

About 3.9% of the U.S. adult population have a lifetime prevalence of bipolar disorder, according to the NIMH. About 2.6% of the population have a 12-month prevalence.

Manic episodes are associated with a long period of feeling "high," or overly happy or irritable. Mood changes associated with a depressive episode include a long period of feeling "low," or empty or worried.

Bipolar II disorder is marked by depressive episodes, shifting with hypomanic episodes. It has no full-blown manic episodes.

Duckworth, a psychiatrist, says the disorder can be difficult to treat at times.

Strategies for treating bipolar II disorder include psychotherapy, a medication regimen, stress management, a regular sleep schedule, aerobic exercise, and recognition of triggers, such as season of the year, says Duckworth, who has not treated Zeta-Jones.

David Miklowitz, a professor of psychiatry at UCLA School of Medicine, says episodes can be triggered by going off one's medications and severe stress, such as job loss.

Miklowitz, who has not treated the actress, says a significant change in a person's sleep cycle or circadian rhythm can be problematic. He recommends regular times for waking up and going to bed.

Duckworth advises people not to work night shifts or varied shifts. He also suggests that people with bipolar disorders exercise regularly, and notes that it is helpful to have loving and supportive relationships.

People usually have out-patient care with medications and psychotherapy, says Miklowitz, author of The Bipolar Disorder Survival Guide. How often people need to adjust their medications varies, he says. Sometimes people need more intensive treatment, such as hospitalization, if they are severely depressed, he adds.

In 2011, the Welsh-born actress spent five days at Silver Hill Hospital, a psychiatric hospital in New Canaan, Conn.

Zeta-Jones, 43, stars as Miranda Wood in the action-comedy movie Red 2, which is out July 19.